Venting closure

ABSTRACT

A sheet metal container closure is provided which has a top panel and a depending skirt for affixation to a container and a sealing liner of resilient deformable material underlying the top panel of the closure for sealing against a sealing surface of the container, and further having a score line centrally located in the top panel of the closure, which score line is rupturable by excessive pressure in a container on which the closure is sealed to provide an aperture in the top panel of the closure through which a portion of the sealing liner can be forced to permit gas to escape from the container between the sealing liner and the sealing surface of the container.

United States Patent 11 1 Lawrence et al.

[54] VENTING CLOSURE [75] Inventors: Kenneth C. Lawrence; James B.

Mills, both of Richmond, lnd.

[73] Assignee: Aluminum Company of America,

Pittsburgh, Pa.

[22] Filed: Sept. 14, 1971 {2!} Appl. No.: 180,259

[52] US. Cl ..2l5/56 [51] lnt.Cl. ..B65d51/l6 [5 8] FieldofSearch..215/56,40,39,42

[56] References Cited UNITED STATES PATENTS 3,310,193 3/1967 MacPherson..2l5/56 3,480,173 ll/l969 Wheaton ..2l5/56 1 51 Jan. 30, 1973 PrimaryExaminerGeorge T. Hall Attorney-David W. Brownlee [57] 4 ABSTRACT Asheet metal container closure is provided which has a top panel and adepending skirt for affixation to a container and a sealing liner ofresilient deformable material underlying the top panel of theclosure forsealing against a sealing surface of the container, and

further having a score line centrally located in the top .panel of theclosure, which score line is rupturable by excessive pressure in acontainer on which the closure is sealed to provide an aperture in thetop panel of the closure through which a portion of the sealing linercan' be forced to permit gas to escape from the container between thesealing liner and the sealing surface of the container.

10 Claims, 6 Drawing Figures VENTING CLOSURE BACKGROUND OF THE INVENTIONNumerous injuries have been caused by bottles which have exploded due toexcessive pressures in the bottles. Excessive pressure may result fromagitation and/or warming of bottles which contain carbonated beveragesor beverages which may be fermented such as wine, beer or fruit juice.When these pressures become too great, either the closure is blown offthe container or the container bursts, throwing particles of glass andother materials which can seriously injure anyone in the area of theexplosion.

It is known to provide bottle closures which have means therein forventing excessive pressures from the containers on which the closuresare sealed. For example, it is well known as is disclosed in U. S. Pat.Nos. 1,865,764; 2,726,002; and 3,310,193 to provide a bottle cap whichhas an aperture in its end wall and an inner liner of elastic materialwhich has either a central perforation or weakened area which willpermit venting of the container when excessive pressures and developedin the container. It is also well known to provide incisions or slits inthe end wall of a closure to provide a vent opening through which gasescan escape from a container as is shown in US. Pat. Nos. 3,059,799 and3,387,765. Another closure has included grooves or thin sections in theliner which permit the liner to flex upwardly under pressure for escapeof the gas from the container as disclosed in U. S. Pat. Nos. 2,265,862;2,735,565; 2,739,724; and 2,514,124. When the pressure in thesecontainers is reduced to a safe value, the sections again seal thecontainer. U. S. Pat. Nos. 2,156,585; 2,174,437; 2,423,295; and2,424,801 disclose metal caps with end walls which can be flexedupwardly by the internal pressures so that the liner can thin bystretching or drawing away from the container sealing surface to permitthe escape of gas from the container between the liner and the sealingsurface.

Although some of the closures described in the above mentioned patentshave provided means for venting some containers, many of them have notbeen well suited for sealing containers with internal pressures of 100pounds per square inch and above. Most such closures have also notprovided continuous metal seals which prevent moisture and/or oxygenpenetration into containers on which they sealed and/or prevent escapeof carbon dioxide or other gases from the containers prior to venting.Accordingly, an improved sheet metal venting closure is desired whichhas a continuous metal top panel and which will seal a container withinternal pressures of approximately 1 pounds per square inch, but whichwill vent pressures in the range of 1 10 to 160 pounds per square inch.

SUMMARY OF THE INVENTION which the closure is sealed to provide anaperture in the LII top panel of the closure for a portion of thesealing liner to be forced through so that gas can escape from thecontainer between the sealing liner and the sealing surface of thecontainer.

Accordingly, an object of the invention is to provide an improvedventing closure which will seal a container having internal pressures ofapproximately 1 10 pounds per square inch, but which will vent pressuresin the range of l 10 to psi.

A further object of the invention is to provide a venting closure with ascore line in its top panel which is rupturable by excessive pressuresin a container on which the closure is sealed.

A further object of the invention is to provide a venting closure madeof metal with a score line centrally located in the top panel of theclosure which will be ruptured by excessive pressures in the containerso that at least a portion of a sealing liner in the closure can beforced through the aperture in the top panel thereby permit gas from thecontainer to escape between the sealing liner and a top sealing surfaceof the container.

Another object of the invention is to provide a venting closure whichwill display obvious evidence of venting.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects andadvantages of the invention will be more fully understood andappreciated with reference to the following description and the drawingsappended thereto wherein:

FIG. 1 is a vertical sectional view of a closure of the invention;

FIG. 2 is a bottom plan view of the closure of FIG. 1 with the linerremoved therefrom;

FIG. 3 is a cross-sectional view taken along line III III of FIG. 2;

FIG. 4 is a side view of the closure sealed on a container in partialcross section;

FIG. 5 is a perspective view of a closure sealed on a container andshowing rupture of the score line and the gasket material projectingfrom the top of the closure; and

FIG. 6 is a fragmentary cross-sectional view of a closure sealed on acontainer showing venting of the gases from the inside of the container.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION A preferredembodiment of a closure of the invention is illustrated in the attacheddrawings and hereinafter described as comprising a roll-on closure witha pilferproof locking band for sealing on a glass or plastic containerwith a threaded finish on its mouth opening. It will be appreciated,however, that the invention can also be practiced with a great varietyof closures such as screw-on closures, crown closures and tear-offclosures among others. A preferred embodiment of a closure of theinvention is further illustrated and described as including a pre-cutdisc liner for sealing against a top sealing surface and a side sealingsurface of a container, but the invention is not limited to such aliner. For example, flowed-in liners or pre-cut disc liners which sealagainst only a top or a side sealing surface of a container can also beused in the practice of the invention.

Referring to FIG. 1, a preferred embodiment of a metal closure of theinvention is identified generally by numeral 10, and comprises a toppanel 12, a depending skirt 14, a locking band 16 attached to theclosure skirt by bridges l8 and a pre-cut disc liner 20 which ispreferably made of a synthetic plastic material such as polyvinylchloride (PVC) or the like. Closure 10 is preferably drawn from a sheetof hard temper aluminum base alloy, and preferably has a thickness of0.008 to 0.0095 inch, although other materials of other thicknesses canalso be used in a closure of the invention. In a preferred embodiment,liner may be cut from a sheet of polyvinyl chloride which isapproximately 0.028 inch thick. The cut liner is positioned in theclosure against the undersurface of top panel 12, and may or may not beadhered to this undersurface.

In the closure which has been selected for purposes of illustration, alocking band 16 is attached to closure skirt 14 by bridges of metal 18which are separated by slits or lances 22 in the skirt. Upon applicationof the closure 10 to a container, the bottom edge of locking band 16 maybe tucked under a locking bead on a container to permanently secure thelocking band on the container. When closure 10 is unscrewed from acontainer, bridges 18 are broken and the top portion of the closure isremoved from the container leaving locking band 16 on the container. Ifthe closure is replaced on a container, the broken bridges indicate thatthe container has been previously opened. A closure of the invention mayalso have vertical weakening lines such as scores, not shown, in itslocking band. These vertical scores may rupture upon removal of theclosure so that the locking band can be removed from the container withthe closure. Closure 10 may also have one or two bands 24 and 26 ofknurling in its skirt 14 to facilitate gripping of the closure tounscrew it from a container, and to re-apply it to the container.

FIG. 2 is a bottom plan view of closure 10 absent liner 20. This showsan l-shaped score 28 with the trunk of the l divisive of top panel 12across approximately -the central one-half of the top panel. Score 28preferably has a cross-section in the shape of a truncated trianglealthough the invention is not limited thereto. Score 28 extends throughat least one-half, and preferably through approximately two-thirds, ofthe thickness of the material in top panel 12 of closure 10 so that thescore can be ruptured by excessive pressures in a container on which theclosure is sealed. The score depth will vary from closure to closuredepending on the material from which the closure is formed, size of theclosure and pressures to be held among other factors. ln one embodimentof a closure of the invention which was formed from aluminumapproximately 0.0095 inch thick, score 28 was cut approximately 0.0062inch deep leaving a residual metal thickness of approximately 0.0033inch.

Turning to FIG. 4, a closure 10 of the invention is illustrated assealed on a container 30 which has a top sealing surface 32, a sidesealing surface 34, threads 36 and a locking bead 38. Closure 10 may beapplied to container 30 by means of a pressure block which applies toppressure against top panel 12 of the closure to seal liner 20 againstthe top sealing surface 32 of container 30 and reforms the marginalportions of the closure and liner from a horizontal plane downward andinward against side sealing surface 34 as is illustrated and describedin U. S. Pat. No. 3,303,955. As described in that patent, one set ofrollers may be moved inward against skirt 14 of closure 10 and rotatedaround the closure to form the skirt against container beads 36, and asecond set of rollers may be moved against the bottom edge of lockingband 16 and rotated around the closure to tuck such edge under lockingbead 38 on the container. This secures closure 10 on container 30 withpressure maintained between liner 20 and top sealing surface 32 and sidesealing surface 34 of the container to provide a tight sealtherebetween. As sealed, the closure-container combination is capable ofcontaining pressures well above atmospheric pressures, and can sealpressures of up to l 10 pounds per square inch (psi) and above.

With prior container-closure combinations, such as that illustrated anddescribed in U. S. Pat. No. 3,303,955, which are capable of sealing highinternal pressures, excessive pressures could sometimes burst thecontainer before the integrity of the seal is broken. It is a feature ofthis invention that the seal between the closure and container will bereleased before such excessively high internal pressures bursts thecontainer.

The definition of excessively high internal pressures depends upon thedesign of the container-closure combination and the liquid which it isto contain. With some containers of light construction, pressures ofover 30 or 40 psi may be considered excessive, whereas in othercontainers of substantial construction, pressures may not be consideredto be excessive until they reach psi or more. According to the presentinvention, the depth, length and shape of the score which is cut in thetop panel of a closure will depend upon the pressures which are to bevented from the container-closure combination. Closure 10 which has beenselected for illustration is designed to vent pressures of over 1 10psi, and preferably in the range of 1 10 psi to l60 psi.

FIGS. 5 and 6 illustrate what happens when a container-closurecombination of the invention has been subjected to excessively highinternal pressures. The internal pressures in container 30 have causedtop panel 12 of closure 10 to dome upwardly rupturing score 28 andforcing a portion of liner 20 through the aperture between the edges ofthe ruptured score. In this preferred embodiment of a closure of theinvention with a substantially elastic PVC liner, the liner has not beenruptured by being forced through the aperture in top panel 12. Instead,gas pressure in container 30 has forced a portion of liner 20 upwardlythrough the aperture to form a bubble projecting above the surface ofthe closure. This draws liner material away from .top sealing surface 32and side sealing surface 34 of container 30 and permits gases in thecontainer to escape therefrom between liner 20 and said top and sidesealing surfaces. The gases can then pass outwardly between thecontainer threads 36 and the closure threads to the outside of thecombination. This relieves the pressure in container 30 to reduce it toa safe pressure which will not burst the container.

It is an advantage of the closure of the invention that once theexcessive pressures have been reduced to a safe value, a seal remainsbetween the closure and container which will prevent leakage of thecontainers contents from the container. Although liner material has beendrawn from the between the closure and sealing surface 32 and 34 topermit venting of excessively high pressures, sufficient liner materialremains to seal against lower pressures and against escape of thecontainers contents.

Another advantage of the invention is that it is apparent from casualobservation that a container-closure combination has vented. Linermaterial continues to project from between the edges of the rupturedscore line after the pressure in the container has diminished to a saferange, and this projecting material makes it obvious that the closurehas vented. This provides a warning that the contents of the containermay have fermented or spoiled and may be unfit for consumption.

lt is therefore seen that a closure and a closure-container combinationhave been illustrated and described which will vent excessive pressuresfrom a container before the container bursts. Although a preferredembodiment of the invention has been illustrated and described, it willbe obvious to one skilled in the art that numerous modifications can bemade in this embodiment without departing from the invention. Forexample, it will be appreciated that the score in the top panel can bemodified to have other score paths, cross sectional shapes or depths aslong as it will rupture when excessive pressures are developed in acontainer on which the closure is sealed. Changes can also be made inthe method of affixation and attachment means, among other details,without departing from the invention.

What is claimed is:

1. In a sheet metal container closure having a top panel and a dependingskirt for affixation to a container and having a sealing liner orresilient deformable material underlying the top panel of the closurefor sealing against a sealing surface of a container, the improvementcomprising a score line centrally located in the top panel of theclosure and cut through a portion of the metal thickness, said scoreline being rupturable by excessive pressure in a container on which theclosure is sealed to provide an aperture in the top panel of the closurefor a portion of the sealing liner to be forced through and therebyfacilitate venting of pressurized gases from the container.

2. A closure as set forth in claim 1 in which the score line isl-shaped.

3. A closure as set forth in claim 1 in which the sealing liner is cutfrom a sheet of polyvinyl chloride.

4. A closure as set forth in claim 1 in which the score line is cutthrough approximately two-thirds of the metal thickness in the top panelof the closure.

5. A closure as set forth in claim 1 in which the score is in theundersurface of the top panel of the closure.

6. In a container-closure combination including a container having asealing surface and a closure having a top panel and a depending skirtaffixed to the mouth of the container and a liner of resilientdeformable material underlying the top panel of the closure and sealingagainst the sealing surface of the container, the improvement comprisinga score line centrally located in the top panel of the closure beingrupturable by excessive pressure inthe container to provide an aperturein the top panel of the closure through which a portion of the sealingliner is forced to facilitate the venting of excessive pressures fromthe container.

7. A container-closure combination as set forth in claim 6 in which thecontainer has a top sealing surface and a side sealing surface againstwhich the liner is sealed, and between which gases are vented when thescore is ruptured in the top panel of the closure.

8. A container-closure combination as set forth in claim 7 in which themarginal edge portion of the top panel of the closure and the liner havebeen deformed downward and inward against the side sealing surface ofthe container.

9. A container-closure combination as set forth in claim 6 in which thescore in the top panel of the closure is I-shaped.

10. A container-closure combination as set forth in claim 6 in which theliner is formed from polyvinyl chloride.

1. In a sheet metal container closure having a top panel and a dependingskirt for affixation to a container and having a sealing liner orresilient deformable material underlying the top panel of the closurefor sealing against a sealing surface of a container, the improvementcomprising a score line centrally located in the top panel of theclosure and cut through a portion of the metal thickness, said scoreline being rupturable by excessive pressure in a container on which theclosure is sealed to provide an aperture in the top panel of the closurefor a portion of the sealing liner to be forced through and therebyfacilitate venting of pressurized gases from the container.
 1. In asheet metal container closure having a top panel and a depending skirtfor affixation to a container and having a sealing liner or resilientdeformable material underlying the top panel of the closure for sealingagainst a sealing surface of a container, the improvement comprising ascore line centrally located in the top panel of the closure and cutthrough a portion of the metal thickness, said score line beingrupturable by excessive pressure in a container on which the closure issealed to provide an aperture in the top panel of the closure for aportion of the sealing liner to be forced through and thereby facilitateventing of pressurized gases from the container.
 2. A closure as setforth in claim 1 in which the score line is I-shaped.
 3. A closure asset forth in claim 1 in which the sealing liner is cut from a sheet ofpolyvinyl chloride.
 4. A closure as set forth in claim 1 in which thescore line is cut through approximately two-thirds of the metalthickness in the top panel of the closure.
 5. A closure as set forth inclaim 1 in which the score is in the undersurface of the top panel ofthe closure.
 6. In a container-closure combination including a containerhaving a sealing surface and a closure having a top panel and adepending skirt affixed to the mouth of the container and a liner ofresilient deformable material underlying the top panel of the closureand sealing against the sealing surface of the container, theimprovement comprising a score line centrally located in the top panelof the closure being rupturable by excessive pressure in the containerto provide an aperture in the top panel of the closure through which aportion of the sealing liner is forced to facilitate the venting ofexcessive pressures from the container.
 7. A container-closurecombination as set forth in claim 6 in which the container has a topsealing surface and a side sealing surface against which the liner issealed, and between which gases are vented when the score is ruptured inthe top panel of the closure.
 8. A container-closure combination as setforth in claim 7 in which the marginal edge portion of the top panel ofthe closure and the liner have been deformed downward and inward againstthe side sealing surface of the container.
 9. A container-closurecombination as set forth in claim 6 in which the score in the top panelof the closure is I-shaped.